Location-based mobile applications have become increasingly popular on smart phones over the past years, such as local search, mobile social networking, mobile advertising etc. Unfortunately, satellite-based positioning systems, an enabler of location based applications, are power-hungry and its intensive usage can drain the battery of mobile devices within a few hours.
Numerous solutions have been proposed to improve the battery life of mobile devices running such applications. One commonly used solution, duty-cycling GPS (global positioning system) sampling intervals puts, for example, a GPS receiver sleep between adjacent location updates and save power consumption. Such a simple solution can improve battery life by acquiring location information less frequently, but can damage the quality of collected location data. Other existing solutions use motion sensor such as accelerometer to turn on or off GPS hardware when user is stationary or moving. Such accelerometer augmented GPS control mechanism may cause undesired GPS measurements, for example, when a user is walking inside a building, and cause an unexpected GPS power-off when the user is moving with a constant velocity on, for example, the highway. There are some other solutions that use current speed information of GPS itself to adjust the sampling rate of GPS. However, these solutions may have serious error propagation as GPS speed information is not accurate sometimes.
It is desirable to have a mobile device that includes power control of location determination receivers.